The present invention relates to a tool for applying a ferrule to a lock wire tethering together a plurality of elements such as threaded fasteners.
In rotating machinery having close tolerances between the rotating and the stationary portions, such as turbines, it is imperative that all objects, no matter how small, be kept from contacting the rotating elements of the machinery. The presence of any foreign object could result in the catastrophic failure of the entire rotating machinery.
Such machinery is inherently complex and requires the usage of many nuts, bolts, screws and other threaded fasteners to assemble all of the components of the machine. Since the operation of such machinery may involve very high rotating speeds and induce vibrations into the machine elements, it is necessary to provide some means for preventing the inadvertent unthreading of the numerous threaded fasteners.
It is known to apply lock wires to tether threaded fasteners together to prevent their inadvertent unthreading. Typically, the lock wire passes through a transverse hole in at least two threaded fasteners and is twisted back on itself in alternating clockwise and counterclockwise directions between the threaded fasteners. The process is duplicated between additional threaded fasteners until the entire threaded fastener pattern has been wired. Following the required stringing and twisting, the lock wire is cut and bent into a certain position.
While the known lock wire has provided satisfactory results, it requires a very time consuming and laborious application process. Due to the dependency upon the operators skill in twisting the lock wire, often the final result is unsatisfactory due to variations in the quantity and tautness of the twists, and the variations in the tension on the lock wire. It has been estimated that annual losses of approximately $10,000,000 are incurred just from re-working unacceptable lock wire assemblies.